JP4289713B2 - Stage apparatus, exposure apparatus, and device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stage apparatus that is used in a projection exposure apparatus, various precision processing machines, various precision measuring instruments, and the like used in semiconductor lithography and requires high-speed and high-precision positioning performance. The present invention also relates to an exposure apparatus and a device manufacturing method using such a stage apparatus.
[0002]
[Prior art]
FIG. 7 is a plan view of a conventional stage apparatus, and FIG. 8 is a cross-sectional view taken along line AA of FIG.
[0003]
7 and 8, reference numeral 17 denotes an XY stage that translates in a horizontal plane on the surface plate 16. Reference numeral 18 denotes a rotary stage mounted on the XY stage 17 via a θ-axis drive linear motor 19θ. Reference numerals 19x and 19y denote linear motors arranged so as to be orthogonal to each other as drive means for translating the XY stage 7 in a horizontal plane. Reference numeral 19y1 denotes a stator of the linear motor 19y, which is fixed on the surface plate 16. Reference numeral 19x2 denotes a mover of the linear motor 19x, which is fixed to the XY stage. When the movement distance of the X axis and the Y axis is long, a plurality of coils of the linear motors 19x and 19y are arranged and moved while sequentially switching (phase switching).
[0004]
A rotary stage 18 is mounted on the XY stage via a linear motor 19θ for driving the θ axis. On the rotary stage 18, X-axis and Y-axis mirrors 20x1 and 20y1 are installed. The XY stage 17 reflects the laser beams from the laser interferometers 20x2 and 20y2 fixed on the surface plate 16. Detect the current position of. Two laser beams are applied to the mirror 20x1 or 20y1, and the amount of rotation of the rotary stage 18 is detected from the difference in measurement values from the interferometer.
[0005]
In this type of stage apparatus, there is a stage apparatus having a vertical movement axis (Z axis) and two orthogonal inclinations (Tilt axes) in addition to the X, Y, and θ axes.
[0006]
FIG. 9 is a block diagram of a conventional driving apparatus for driving such a stage apparatus. In the figure, the X-axis, Y-axis, and θ-axis displacements of the movable stage 11 detected by the laser interferometer are respectively taken from the corresponding target values and input to the compensators 12X, 12Y, and 12θ. . In each compensator 12X, 12Y and 12θ, a command value to each linear motor is determined by PID control or the like.
[0007]
Usually, when one linear motor 19x, 19y or 19θ is driven, the force that causes displacement with respect to the other drive shaft from the positional relationship between the gravity center position of the stage 11 and the action point of the linear motor 19x, 19y or 19θ, That is, an interference force is generated. Due to this interference force, a displacement occurs with respect to the drive shaft that does not need to be driven, which causes a problem that it takes a long positioning time and a predetermined posture cannot be maintained. For this reason, from the command value determined by the compensator 12X, 12Y or 12θ of each drive axis, the command value that cancels the influence on the other drive shaft is output by the non-interference means 13, and this is compensated for the other drive shaft. By adding to the command value output by the device 12X, 12Y or 12θ, the displacement of other drive shafts is prevented and the positioning time is shortened.
[0008]
[Problems to be solved by the invention]
However, the characteristics of the stage 11 may change depending on the position and posture of the stage 11. For this reason, even when each drive means is driven by the same command value determined by the compensators 12X, 12Y, and 12θ of each drive axis, the amount of interference generated on the other drive axes causes the position and orientation of the movable stage 11 to move. May vary. Therefore, even if the non-interacting command is output based on the command value, the driving force is different and the displacement occurrence may not be sufficiently removed.
[0009]
For example, in the linear motor 19x, 19y, or 19θ, the thrust constant varies depending on the relative position between the coil and the magnet, and therefore the generated driving force is different even for the same command value. As a result, the influence on the other drive shafts also varies depending on the driving force. Therefore, even if the non-interacting command is output based on the command value, the driving force is different and the displacement may not be sufficiently removed.
[0010]
Furthermore, in a scanning type exposure apparatus that is expected to become the mainstream in the future, exposure is performed when the stage is moving at a constant speed, so there is a need to maintain the stage posture with high accuracy not only when stopped but also during movement. is there.
[0011]
The first object of the present invention is to generate an appropriate non-interference command regardless of the position and orientation of the stage, to sufficiently remove the displacement generated in the other shaft when driving a certain drive shaft, and to perform positioning. It is intended to shorten time and reduce posture fluctuation.
[0012]
The second object of the present invention is to generate an appropriate non-interacting command regardless of the position of the laser beam from the interferometer that hits the mirror, so that no deviation occurs even when the stage is moving at a constant speed. It is what you want to do.
[0013]
[Means for Solving the Problems]
In order to solve the above problems, a stage apparatus of the present invention includes a stage movable along a plurality of drive axes, a drive mechanism for driving the stage along each drive axis, and each drive axis of the movable stage. A detector for detecting the position or speed of the motor, a compensator for giving a command to the drive mechanism to match the position or speed detected by the detector for each drive axis with a predetermined target value, and for a certain drive axis A non-interacting means for generating a command for canceling the displacement of the stage generated on the other drive shaft when the stage is driven based on the command generated by the compensator of the drive shaft; An addition means for adding the command value generated by the compensator for the drive shaft and the command value generated by the non- interacting means and outputting the sum to the drive mechanism, and the non- interacting means cancels the displacement of the stage. Command It characterized by having a high-pass filter to act against.
[0014]
In addition, it is desirable to have a non-interacting coefficient correcting unit that corrects the non-interacting coefficient of the non-interacting unit based on at least one of the position or orientation of the stage.
[0015]
Preferably, an interferometer is used as the stage position detecting means, and the non-interacting coefficient correcting means corrects the non-interacting coefficient of the non-interacting means according to the position where the measurement light hits the mirror. That is good.
[0016]
In addition, the stage apparatus of the present invention is capable of translation along a translational drive axis in a plane and rotatable around the rotation drive axis in the plane, and rotates the stage along the translational drive axis. A driving mechanism for driving around the driving axis of the stage, a detector for detecting the position of each stage on each driving axis, and the driving for matching the position detected by the detector for each driving axis with a predetermined target value. A compensator that gives a command to the mechanism, and a compensator for the rotational drive shaft generates a command to cancel the displacement of the stage that occurs about the translational drive shaft when the stage rotates about the rotational drive shaft Decoupling means generated based on the received command, and adding means for adding the command value generated by the compensator for the translational drive shaft and the command value generated by the non-interacting means and outputting to the drive mechanism And have , Non-interference means, characterized in that it has a high-pass filter which acts on command to cancel the displacement of the stage.
[0017]
Further, it is desirable that the stage is controlled to travel at a constant speed.
[0018]
An exposure apparatus provided with the above stage apparatus and a device manufacturing method using the same also fall within the scope of the present invention.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
<Embodiment 1>
FIG. 1 shows a block diagram of a driving apparatus according to the first embodiment of the present invention.
[0020]
The difference between the control amount (position, velocity or acceleration) of the stage 1 and the measurement value detected by the laser interferometer is input to each compensator 2. The compensator 2 for each axis (X, Y, θ) has a command value determined by a control means such as PID control. The command value is input to the non-interference means 3 between the axes. The non-interacting means generates a non-interacting command for canceling a displacement generated in another axis when a certain axis is driven with the command value. The command value determined by the compensator 2 and the non-interacting command generated by the non-interacting unit 3 are added by the adding unit 5 and input to the driving unit of each axis. The driving means for each axis drives the stage by generating thrust based on the input command value. The non-interacting coefficient correcting unit 4 corrects the coefficient of the non-interacting unit based on the position and orientation of the stage detected by the laser interferometer.
[0021]
FIG. 2 shows the displacement generated in the X and Y axes when the θ axis rotates.
[0022]
Similar to the above-described stage apparatus, X-axis and Y-axis mirrors 10 are provided on the rotary stage, and the stage reflects the laser light from the laser interferometer fixed on the surface plate 6. Detect the current position of. Further, two laser beams are applied to the X axis or the Y axis (Y axis in the figure), and the rotation amount of the rotary stage 8 is detected from the difference between the measured values from the two interferometers.
[0023]
The position where the laser light hits the mirror varies depending on the position of the XY stage. Further, when the mirror installed on the rotary stage is rotated by the rotation of the θ axis, the position where the laser light hits the mirror is different. For this reason, when the laser beam hits a position away from the rotation center of the θ axis, even if the XY stage does not move in the X axis and Y axis directions, the position where the laser beam hits the mirror only by rotating the rotary stage. Changes, the measurement values of the laser interferometer in the X-axis and Y-axis directions change.
[0024]
Such a change in the measurement value of the laser interferometer becomes a position error in the X-axis and Y-axis directions, which may cause an increase in positioning time and a deterioration of the posture system. Therefore, it is necessary to generate a command for canceling the change in the XY-axis direction of the position where the laser beam generated when the rotation stage rotates by the θ-axis by the non-interference means 3.
[0025]
The change in the XY-axis direction at the position where the laser beam generated when the rotation stage rotates by the θ-axis differs depending on the positional relationship between the laser beam and the θ-axis rotation center. For example, the amount of displacement at the position where the laser beam hits the mirror increases in proportion to the distance from the center of rotation.
[0026]
Therefore, it is necessary to measure at which position of the mirror the laser light hits and to correct the non-interference factor accordingly. For example, the position at which the laser beam strikes the X-axis direction measuring mirror may be corrected with the non-interacting coefficient based on the position of the stage in the Y-axis direction.
[0027]
In the non-interacting coefficient correction means, a relational expression between the position / posture of the stage and the coefficient value is held. Based on this relational expression, a coefficient value is calculated and obtained from the position / posture of the stage detected by the laser interferometer. For example, from the position measurement result in the Y-axis direction of the stage, the distance between the position where the laser beam hits the X-axis direction measurement mirror and the θ-axis rotation center is obtained, and an appropriate coefficient is applied to this to shift from the θ axis to the X axis. Find the decoupling factor. Similarly, the distance between the position where the laser beam hits the Y-axis direction measurement mirror and the θ-axis rotation center is obtained from the position measurement result of the stage in the X-axis direction, and an appropriate coefficient is applied to this distance from the θ-axis to the Y-axis. Is obtained.
[0028]
However, when the stage moves at a constant speed in the X direction or the Y direction, such as during scan exposure, the decoupling factor from the θ axis to the Y axis or the decoupling factor from the θ axis to the X axis is As it moves, it changes like a ramp in proportion to the position. For this reason, even if the output from the compensator of the θ axis does not change, the non-interference term from the θ axis to the Y axis or the X axis changes in a ramp shape. The command due to such a change is not a command generated because the θ-axis is driven, and therefore acts as a disturbance, not as a non-interacting command for suppressing the original interference with the Y-axis and the X-axis. Usually, since the compensator includes an integrator, the steady-state deviation can be eliminated for a constant value disturbance, but a steady-state deviation is generated for a ramp-shaped disturbance.
[0029]
In order to avoid such a steady deviation, the stage apparatus of the present invention uses high-pass filters for the non-interacting means 3θx and 3θy. The high-pass filter is represented by a differential plus first-order delay as shown in the following equation.
[0030]
y = {k · s / (s + ω)} × u
Here, y is an output, u is an input, ω is a corner frequency of the high-pass filter, k is a gain, and is determined by the non-interacting coefficient correcting means.
[0031]
k is proportional to the position as described above, but has a proportional relationship to time when the stage moves at a constant speed as in scan exposure,
k = k ′ / s
It is expressed as So overall,
y = {k ′ / (s + ω)} × u
Thus, the integral characteristic is canceled.
[0032]
In this way, the ramp disturbance has an integral characteristic in the frequency domain, so that a steady deviation is generated. A steady deviation can be prevented.
[0033]
FIG. 3 is a diagram showing an outline of frequency characteristics of the stage apparatus of the present embodiment.
[0034]
For the input / output characteristics of each axis, the interference characteristics are mountain-shaped with the peak frequencies substantially matching. Therefore, almost no interference occurs in the low frequency region. On the other hand, the high-pass filter has a low-frequency cutoff characteristic, but by setting its corner frequency lower than the band where the interference is significant, the non-interference command in the frequency band where interference occurs passes through the high-pass filter. Therefore, the non-interference performance is not affected.
[0035]
According to the stage apparatus of this embodiment, an appropriate non-interacting command is generated regardless of the position and orientation of the stage, and the displacement generated in the other shaft when a certain drive shaft is driven is sufficiently removed. Thus, the positioning time can be shortened and the posture fluctuation can be reduced. Further, no deviation occurs even when the stage is moving at a constant speed.
[0036]
The stage apparatus of the present invention is not limited to a stage apparatus that moves only to the XYθ axes, and can be similarly applied to any stage apparatus having a plurality of drive axes. For example, the stage may be movable in the Z direction or the Tilt direction.
[0037]
In the stage apparatus of the present invention, the high-pass filter is provided in the non-interacting means 3θx, 3θy. However, the present invention is not limited to this, and a high-pass filter may be provided in other non-interacting means.
[0038]
<Embodiment 2>
Next, an embodiment of a scanning exposure apparatus in which the stage apparatus of the above-described embodiment is mounted as a wafer stage will be described with reference to FIG.
[0039]
The lens barrel surface plate 96 is supported from the floor or base 91 via a damper 98. The lens barrel surface plate 96 supports the reticle surface plate 94 and also supports a projection optical system 97 positioned between the reticle stage 95 and the wafer stage 93.
[0040]
The wafer stage is supported on a stage surface plate supported from a floor or a base, and the wafer is placed and positioned. Further, the reticle stage is supported on a reticle stage surface plate supported by a lens barrel surface plate, and is movable by mounting a reticle on which a circuit pattern is formed. Exposure light for exposing the reticle mounted on the reticle stage 95 onto the wafer on the wafer stage 93 is generated from the illumination optical system 99.
[0041]
Wafer stage 93 is scanned in synchronization with reticle stage 95. During scanning of the reticle stage 95 and the wafer stage 93, the positions of the both are continuously detected by the interferometers and fed back to the driving units of the reticle stage 95 and the wafer stage 93, respectively. As a result, both scanning start positions can be accurately synchronized, and the scanning speed of the constant speed scanning region can be controlled with high accuracy. While both are scanning the projection optical system, the reticle pattern is exposed on the wafer, and the circuit pattern is transferred.
[0042]
In this embodiment, since the stage apparatus of the above-described embodiment is used as a wafer stage, an appropriate non-interacting command is generated regardless of the position and orientation of the stage, and when a certain drive shaft is driven, Can be sufficiently removed, positioning time can be shortened, and posture fluctuation can be reduced. Further, no deviation occurs even when the stage is moving at a constant speed as in scan exposure.
[0043]
<Embodiment 3>
Next, an embodiment of a semiconductor device manufacturing method using the above-described exposure apparatus will be described. FIG. 5 shows a manufacturing flow of a semiconductor device (a semiconductor chip such as an IC or LSI, or a liquid crystal panel or a CCD). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. In step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 14, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). . In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step S7).
[0044]
FIG. 6 shows a detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is printed onto the wafer by exposure using the exposure apparatus described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. By using the manufacturing method of this embodiment, it is possible to manufacture a highly integrated semiconductor device that has been difficult to manufacture.
[0045]
【The invention's effect】
According to the stage apparatus of the first aspect of the present invention, when a high-pass filter is used, an appropriate non-interacting command is generated regardless of the position and orientation of the stage, and when a certain drive shaft is driven, It is possible to sufficiently remove the displacement generated in the shaft, shorten the positioning time, and reduce the posture fluctuation.
[0046]
Further, according to the stage device of the seventh aspect, even when the stage is traveling at a constant speed, it is possible to generate an appropriate non-interacting command and prevent a deviation.
[Brief description of the drawings]
FIG. 1 is a block diagram of a stage apparatus driving apparatus according to a first embodiment. FIG. 2 is a diagram showing displacement generated in the XY axis direction when the θ axis rotation of the stage apparatus driving apparatus according to the first embodiment is performed. FIG. 4 is a front view of the exposure apparatus of the second embodiment. FIG. 5 is a semiconductor device manufacturing flowchart. FIG. 6 is a wafer process flowchart. FIG. 8 is a cross-sectional view taken along line AA in FIG. 7. FIG. 9 is a block diagram of a conventional stage apparatus driving apparatus.
DESCRIPTION OF SYMBOLS 1 Stage 2 Compensator 3 Non-interference means 4 Non-interference coefficient correction means 5 Adder 10 Mirror 91 Floor / base 92 Stage surface plate 93 Wafer stage 94 Reticle surface plate 95 Reticle stage 96 Lens barrel surface plate 97 Projection optical system 98 Damper 99 Illumination optical system

Claims (12)

A stage movable along a plurality of drive axes;
A drive mechanism for driving the stage along each drive axis;
A detector for detecting the position or velocity for each drive axis of the stage;
A compensator that gives a command to the drive mechanism to match the position or velocity detected by the detector for each drive axis to a predetermined target value;
Decoupling means for generating a command to cancel the displacement of the stage generated for another drive axis when the stage is driven for a drive axis based on the command generated by the compensator of the drive axis; ,
Adding a command value generated by a compensator for the other drive shaft and a command value generated by the non-interacting means, and outputting to the drive mechanism;
A stage apparatus comprising: a high-pass filter that causes the non- interacting means to act on a command to cancel the displacement of the stage. The stage apparatus according to claim 1 , wherein the stage is movable in a two-dimensional translation direction in a plane and a rotation direction in the plane. A stage that is translatable along a translational drive axis in a plane and rotatable about a drive axis of rotation in the plane;
A drive mechanism for driving the stage along a translational drive shaft and around a rotational drive shaft;
A detector for detecting the position of each drive axis of the stage;
A compensator that gives a command to the drive mechanism to match the position detected by the detector for each drive axis to a predetermined target value;
Non-interference that generates a command to cancel the displacement of the stage generated on the translational drive shaft when the stage rotates about the rotation drive shaft based on the command generated by the compensator of the rotation drive shaft And
Adding the command value generated by the compensator for the translational drive shaft and the command value generated by the non-interacting means, and outputting to the drive mechanism;
A stage apparatus characterized in that the non-interacting means has a high-pass filter that acts on a command to cancel the displacement of the stage. According to the non-interacting any one of claims 1-3, characterized in that the coefficients having a non-interference coefficient correcting means for correcting, based on at least one of the position or attitude of the stage of the non-interference means Stage equipment. The stage apparatus according to any one of claims 1 to 4, wherein an interferometer is used as the stage position detecting means. 6. The stage apparatus according to claim 5, wherein the non-interacting coefficient correcting unit corrects the non-interacting coefficient of the non-interacting unit according to a position where the measurement light hits the mirror. The stage includes a stage device according to any one of claims 1 to 6, characterized in that the constant speed running control. Exposure apparatus characterized by having a stage apparatus according to any one of claims 1 to 7.   9. The exposure apparatus according to claim 8, wherein the stage apparatus is provided as a wafer stage.   10. An exposure apparatus according to claim 8, wherein the projection optical system is driven to scan the wafer and the reticle, and the reticle pattern is exposed on the wafer. A step of preparing an exposure apparatus according to claim 8 to 10 any one, a step of holding the wafer on the stage, device manufacturing method characterized by a step of exposing the reticle pattern onto the wafer .   The device manufacturing method according to claim 11, further comprising a step of applying a resist to the wafer and a step of developing the exposed wafer.

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